How to end friend relationships on FB, but keep sisters in sorority

On FB homepage, click on friends, all friends, and when list comes up, click the X at the right of a person who you want to end as a friend on FB and then click remove when it asks you.  This person will still be a sister in your sorority if they have already joined.  Do not remove them as soon as they become a friend, make sure they have joined your house first.  Good Luck and see you on FB and SL.